Polymerization in the presence of an organo-phosphorus compound as an activator



Patented Feb. 27, 1951 POLYMERIZATION IN THE PRESENCE OF ANORGANO-PHOSPHORUS COMPOUND A AN ACTIVATOR John A. Lorltsch, Sootia, N.Y., assignor to General Electric Company, a corporation of New York NoDrawing. Application July 28, 1948, Serial No. 885,773

8 Claims. (Cl. 260-454) This invention relates to the polymerization ofcompounds containing polymerizable groupings. More particularly, thisinvention is concerned with a method of accelerating the rate ofpolymerization of a substantially non-aqueous polymerizable systemcontaining an organic oxygen-releasing peroxide catalyst and apolymerizable compound capable of being polymerized by theaforementioned organic catalyst, e. g., a polymerizable compoundcontaining a CH2=C grouping or a CH=CH- grouping which method comprisesincorporating in the said system a small amount of an organic reducingagent capable of being oxidized by the addition of an atom of oxygenreleased from the said organic catalyst, and thereafter efiectingpolymerization of the resulting mass.

In the polymerization of chemical compounds,

or compositions containing polymerizable groups or radicals of the typedisclosed above (for brevity referred to hereinafter as thepolymerizable compounds), it is often desired to accelerate theconversion of the monomeric material or, in some cases, a substantiallyunpolymerized material to the polymeric form or substantiallypolymerized state. For this purpose, catalysts are incorporated in thepolymerizable mixture. However, despite the use, in some cases, of quiteactive catalysts, e. g., benzoyl peroxide, aluminum chloride, etc., itis often difficult to efi'ect the accelerated polymerization withoutobtaining products having certain defects.

For instance, when benzoyl peroxide is employed as a catalyst for thepolymerization of a polymerizable system containing an unsaturatedaliphatic alcohol ester of a polycarboxylic acid, e. g., diallylphthalate, and a polyhydric alcohol ester of an alpha unsaturated alpha,beta polycarboxylic acid (said polyhydric alcohol ester being oftenreferred to as an unsaturated alkyd resin) e. g., diethylene glycolmaleate, great care must be exercised in effecting the polymerization.If too large an amount of benzoyl peroxide is employed, the type ofcopolymer obtained will be inferior due to the low molecular weight ofthe product. If a small amount of benzoyl peroxide is employed, thetimev for effecting reaction is greatly extended. In addition, if thetime for effecting polymerization is attempted to be decreased byheating the polymerizable mass at higher temperatures, quite often thepolymerized product will contain bubbles, cracks, voids, etc. I have nowdiscovered that polymerizable systems of the kind mentioned in the firstparagraph of this specification, more particularly such systemscomprising polymerizable material containing a CH2=C radical or aplurality of such radicals, or polymerizable material (other than, e.g., drying and semi-drying oils and acids thereof containing a CH=CH--radical or plurality of such radicals, may be polymerized at a muchfaster rate than has heretofore been possible to produce polymerizedproducts having an appearance and properties comparable to productspolymerized for much longer periods of time in accordance with thebetter techniques now employed in the art.

' reducing compound as illustrated, e. g., by the V In acordance withthe practice of the more specific embodiments of my invention, I am ableto effect more rapid conversion of the abovedescribed polymerizablematerials or compositions of matter to the finally polymerized state byincorporating in the polymerizable material (e. g., the polymerizablecompound or compounds) a small amount of an organic oxygenreleasingperoxide catalyst, adding to the polymerizable system a small amount ofan organic following groups of compounds: 1) organic reducing compoundscorresponding to the general formula g R RI-i-R where R is selected fromthe class of substituents consisting of organic radicals, for instance,alkyl, aryl, alkaryl, aralkyl radicals, alkoxy, and aryloxy radicals,and R is theasame as R and in addition may be a substituent selectedfrom the class consisting of hydrogen and hydroxy substituents;

a more specific example of such class being organic compounds containingphosphorus and an oxygen atom attached directly to the phosphorus atom,e. g., organophosphorus compounds having the general formula where R andB have the same meaning as disclosed above. One of the requirements forthe above-disclosed organophosphorus and organosulfur compounds is thatthese compounds contain a phosphorus or sulfur atom the valence of whichcan be increased by the addition of an atom of oxygen released from theperoxid catalyst.

In practicing the present invention, it is essential that certainprecautions be taken in the type of organic peroxide or type of organicreducing compound employed. For example, certain organic peroxidecatalysts, for instance, benzoyl eroxide, exert no additionalaccelerating efiect on the polymerization of the generically describedpolymerizable compounds (or compositions) when used in conjunction withthe organic reducing agent of the type disclosed above when comparedwith the case where the organic reducing agent is absent. The reason forthis is not clearly understood. However, one explanation for this maydepend upon the manner in which benzoyl peroxide dissociates.

Benzoyl peroxide, for example, dissociates in the presence of a reducingagent of the type disclosed above according to the following equation:

From the above manner in which benzoyl peroxide dissociates, it will beapparent that there is no oxygen released which is capable of oxidizingan organic reducing agent by an attachment of the oxygen to the reducingagent. The absence of oxygen in the dissociation (decomposition) ofbenzoyl peroxide is substantiated by the work of Hey and Walters asreported in Chem.

'Rev., 21, 169 (1937), and by McClure, Robertson 4 lieved to proceed asillustrated, e. g., by tertiary butyl hydroperoxide:

oiHr-o. .OH

C4119. H. O2T

In the presence of the usual types of inhibitors, e. g., hydroquinone,the dissociation proceeds accordingto (a) and (b) of the above equation.This reaction is shown by the following equation:

(a) o 011 II (Jim-0+ .OH canon 11,0 I i However, when tertiary butylhydroperoxide is used with the type of reducing agent employed in thepractice of my invention, the reaction of this type of reducing agent,e. g., phenyl phosphinic acid, whose formula may be written as means ofan equation, the reaction would appear as follows:

The free radicals when thus released in a reactive medium are believedto initate polymerization which causes the polymerization to proceed atan accelerated rate.

Generally, in accordance with the practice of my invention, it isbelieved that all reducing agents which reduce by acquiring an atom ofoxygen promote the acceleration effect. Those reducing agents whichreduce by furnishing protons to another molecule, do not promoteacceleration, but rather promote retardation of the polymerization.Stated alternatively, the acceleration effect is brought about by freeradicals released by the reaction between the proper peroxide catalystand the proper accelerator, the type of accelerator and peroxide useddetermining the effect produced.

My invention may be applied to the polymerization of variouspolymerizable monomers and mixtures of monomers. These include, e. g.,the various polymerizable materials or monomers containing the CH2=Cgrouping, for instance,

styrene, substituted styrenes, e. g., dichlorostyrene, divinyl benzene,vinyl ethylbenzene etc.; acrylic and methacrylic acids and derivativesthereof including the nitriles of the said acids; e. g., acrylonitrile,the amides of the said acids, e. g., acrylamide, esters of an acrylicacid of the general formula tion where R may be hydrogen and, inaddition, may be a halogen Jr a hydrocarbon radical, more particularlyone selected from the class consisting of alkyl, aryl, alkaryl, andaralkyl' radicals, and R may be a substituted (e. g., halogenated) or anunsubstituted hydrocarbon radical which'may be the same as R, forexample, ethyl acrylate, butyl acrylate, methyl methacrylate, propylmethacrylate, propyl alpha-chloroacrylate, benzyl acrylate, tolylacrylate, chlorobenzyl acrylate, etc.; polyesters of acrylic acids, e.g. ethylene diacrylate, etc., allyl and methallyl ethers and allyl andmethallyl esters of monocarboxylic and polycarboxylic saturated andunsaturated acids, both aliphatic (e. g., alkyl and alkenyl) andaromatic acids, e. g., vinyl allyl ether, diallyl phthalate, dimethallylphthalate, diallyl tetrachlorophthalate, diallyl carbonate, diallylmaleate, allyl alloxyacetate, allyl acetate, diallyl succinate, etc.;vinyl ethers and esters, e. g., divinyl ether, vinyl esters of saturatedand unsaturated aliphatic monocarboxylic and polycarboxylic acids, e.g., vinyl acetate, vinyl propionate, vinyl butyrate, divinyl oxalate,vinyl acrylate, vinyl crotonate, etc.; vinyl ketones, e. .g., divinylketone, vinyl ethyl ketone etc. saturated and unsaturated monohydric andpolyhydric alcohol esters of unsaturated polycarboxylic acids of theitaconic acid type, c. g., diethyl itaconate, diallyl itaconate,ethylene glycol itaconate, diethylene glycol itaconate, glycerylitaconate, methyl citraconate, dimethallyl citraconate, diethylmesaconate, diallyl mesaconate, etc.; vinyl halide compounds, e. g.,vinyl chloride, vinyl bromide, etc.; diolefin compounds, e. g.,butadiene-1,3,2- methyl butadiene-1,3 chloroprene, 2-cyanobutadiene-L3,etc.

Among the compounds containing a grouping which may be polymerized inaccordance with the concept of my invention, are, e. g., saturated andunsaturated, monohydric and polyhydric alcohol esters of alphaunsaturated alpha, beta polycarboxylic acids, for instance, diethylfumarate, diethyl maleate, dibutyl fumarate, ethylene glycol maleate,ethylene glycol fumarate, propylene glycol maleate, diethylene glycolmaleate, propylene glycol fumarate, glyceryl maleate, diallyl maleate,diallyl fumarate, dimethallyl maleate, etc. It will be understood bythose skilled in the art, that mixtures of compounds containing theCH2=C grouping and the -CH=CH-- grouping may also be employed as thepolymerizable materials.

, Various suitable reducing agents may be employed which in the presenceof the proper organic peroxide catalyst accelerate the polymerizaof theabove-described polymerizable compounds. These include, e. g., organiccompounds containing a phosphorus atom to which an oxygen atom isattached directly to the phosphorus atom, the valence of which can beincreased by the addition of an oxygen atom released from the organicoxygen-releasing peroxide catalyst, for instance, alkyl phosphinicacids, e. g., butyl phosphinic acid, etc.; aryl phosphinic acids, e. g.,phenyl phosphinic acid; dialkyl hydroxy phosphines, e. g., diethylhydroxy phosphine; diaryl hydroxy phosphines, e. g., diphenyl hydroxyphosphine, etc.; alkyl aryl phosphinates, e. g., dibutyl phenylphosphinate; aryl alkyl phosphinates, e. g., diphenyl butyl phosphinate,etc.; diaryl aryl phosphinates, e. g.,

diphenyl phenyl phosphinate, etc.; alkyl and 15 aryl phosphites, e. g.,phenyl phosphite etc.; organic reducing compounds containing a sulfuratom to which an oxygen atom is attached directly to the sulfur atom,the valence of which can be increased by the addition of an oxygen atomreleased from the organic oxygen-releasing peroxide catalyst, e. g.,alkyl and aryl sulfltes, for instance, alkyl sulfites, e. g., ethylsulflte, n-butyl sulfite, aryl sulfltes, e. g., phenyl sulflte etc; Theforegoing compounds are only illustrations of the broad class ofcompounds which can be employed as accelerators within the broad scopeof my claimed invention. It is, of course, understood, that mixtures ofthe above mentioned reducing agents (accelerators) may also be employed.

The amount of reducing agent employed may be varied depending on suchfactors as, e. g., the type of polymerizable materials employed,reaction products desired, temperature conditions, etc. Usually theamount, by weight, may be varied from about 0.01 to 10 per cent of theweight of the polymerizable materials. I prefer to employ from about 0.1to 4 or 5 per cent, since no particular advantage is obtained by usingamounts substantially in excess of these amounts.

As was stated previously not all organic peroxides are suitable for usein the practice of my invention. Only those organic peroxides which canbe induced to give up an atom of oxygen in the presence of the organicreducing agent, many examples of which have been given above, may beused. These include, e. g., acetylbenzoyl peroxide, isopropyl tertiarybutyl peroxide, tertiary butyl hydroperoxide, diheptanol peroxide,tertiary butyl perbenzoate, ditertiary butyl di,-.

perphthalate, tertiary butyl perfuroate, ditertiary butyl diperadipate,ditertiary butyl dipersuccinate, l-hydroxy cyclohexyl hydroperoxide-l,tertiary amyl hydroperoxide, diacetyl peroxide, etc., as well asothersuitable aliphatic (e. g., alkyl), aromatic or mixed aliphatic andaromatic (e. g., mixed alkyl aryl) peroxides, peracids, hydroperoxides,peracid esters, etc. The amount of organic oxygen-releasing peroxidecatalyst employed may also be varied over a wide range depending, forexample, on the polymerizable materials employed, products desired,temperature conditions, etc. Usually I may employ from about 0.1 to ashigh as 8'or 10 per cent by weight of the polymerizable materials. Iprefer to employ an amount of the organic peroxide catalyst equal tofrom 0.25 to about 5 per cent,

by weight, of the polymerizable materials.

In order that those skilled in the art may better understand howthepresent invention may be practiced, the following examples are given byway of illustration and not by way of limitation. All parts are byweight.

Example 1 In this example diallyl phathalate and diethylene glycolmaleate'were copolymerized in varying proportions using differentorganicperoxide catalysts employed in the practice of my tem was allowedto stand at room temperature until it was determined that the mixturehad gelled. The time required to arrive at this gel stage was taken asthe "Average time to gel at room temperature. All parts are by weight.

Diethyl- Phenyl fi Sample Diellyl ene Phosme No. Phthalato I GlycolCatalyst phinic 38% Maleate Acid Temp.

Parts Parts Parts Home 1- 67 33 Benzoyl peroxide, 1 part None 120 2- 6733 fin 2 3 67 33 Diheptanol peroxide, 1 part-. None About 340 4. e7 33fin V 2 1 5.-. 50 50 Tertiary butyl perbenzoete, 1.5 parts None 50 6...o 50 (In 1. s 4 7... 50 50 Ditertlary Butyl Diperphthalate, 1.5 partsNone 55 8- 50 5O d A 1. 5 4 9. 50 50 Tertiary Butyl Perluroate 1.6parts..--- None 79 10 50 50 1. 5 6 11 5O 50 Ditertiary ButylDlperadipate, 1.5 parts None 55 12 50 50 0 1. 5 7 1; 50 50 DitertiaryButyl Dlpersuecinate, 1.5 parts.. None 85 14 50 50 do 1. 5 12 15 67 33l-hydroxy cyclohexyl hydroperoxide-l, 1 part None 300 16. 67 33 do 1 1217. 67 33 Tertiary emyl hydroperoxide, 1 part N one 320 1B 67 33 do 1 1219 50 50 Dlacetyl peroxide 1.5 parts None 20 20.. 50 5O 2 3 21. 50 50Aeetyl benzoyl peroxide 1.5 parts None 20 22. 50 50 d n 2 6 23.. 50 5ODitertiary butyl peroxide 1.5 parts None 90 24.. 50 50 1.5 94 50 50 Nnne None 96 26. 50 60 2 Greater than 1080 Example 2 for 15 hours at 110C; In every sample exce t This example illustrates the results obtainedby the one in which phenyl phosphinic acid was abpolymerizing a mixtureof polymerizable materials comprising diallyl phthalate and diethyleneSent genmg curred after the at glycol maleate in the presence oftertiary butyl emperature. The "Remar l:s in the followin hydroperoxideand using various reducing agents, table are con eme o it the a e r n fincluding reducing agents which are known to be. c a my w h pp Ce 0inhibitors per Se for the polymerization of the the castings afterheating at the elevated temaforementioned polymerizable materials.perature (110 C.)

- Parts Di- Average Time Parts Dral- Sample ethylene To Gel At N L lylllgltlsha Glycol Parts Catalyst Accelerator Room Temp Maleate In Hours67 33 1 None 340. 50 (in 216. 50 50 144. 50 50 Tertiary Butyl catechol,2 parts.-- Giezzter than 50 50 Guaiacol, 2 parts 150. 50 50 Quinone, 2parts Do. 67 33 Phenyl phosphinic acid, 2 parts.-- 12. 67 33 n-Butylsulflte, 2 parts 12. 67 33 Diphegyl hydroxy phosphine, 2 60.

par 50 .50 Diphenyl phenyl phosphinate, l 5.

par 100 Benmyl Peroxide, 6. None 67. 100 100 -.do n-Butyl sulflte, 3parts 72.

Example 3 Parts Parts Parts This example illustrates the advantage whicham. Parts Tertiary Phenyl ethylene can be taken of being able topolymerize mate- 13 g. P t l i a l z i te 1 1 312 553%.. Remarks rials,e. g., a mixture of diallyl phthalate and Pmxide Acid diethylene glycolmaleate, at a faster rate and 134 66 2 None Very hard, many still obtainproducts which have better properties 134 66 2 2 g g i two than those ofproducts obtained by efiecting polylarge cracks. merization of the samematerials in omitting the 134 66 2 3 s all z i ckg accelerating systemembodied in my invention. 134 66 2 ck s f no In each case thepolymerizable materials were Z B3;

placed in a glass tube and examined for gelling properties at the end Of20 hours at room temt Thistsamplgishoi i'eflil noflsligns ofgelling'aftler 20 hours at room perature. Thereafter each sample washeated 76 texrliliepera ure w 1 e a c 0 er samp cs were a ready gelledat that 7 9,548,685 9 Example 4 This example demonstrates that otherpolymerizable systems may be copolymerized in aceordance with my'claimedinvention to obtain acceleration of the polymerization of such sys- 5feasible to employ the gelled materials for molding compositions bygriding the gelled particles and molding the'same under heat andpressure.

Even though solventless mixtures of the polymerizable materials may beemployed for coating tems. or other purposes specified previously,solution of 13 Polymeriznble Composition Peroxide Catalyst Accelerator Tfi gg -v 1 Styrene, 40 parts; Propylene glycol Tertiary butyl hydro-None-.- 14.

furnaratemrbate, 60 parts. peroxide, 2 parts. Same as 1 Same as 1 PhenylPhosphmic 0.5,

\ acid, 2 parts. Butyl mcthacrylate 33 parts do None Castor oilvinalkyd, 67 ports--- do 45 Same as 3.. dc Same as 2 2 Diallylphthalate, 100 parts. -s- Tertigryzbutyl perben- N e 8.35 mlnutegj zoa eer s. Same as 5 Same at 5? Same as 2. 5,4 minutes;

Methyl methacrylate 100 Tertii iry lz igyg perben 96.

zoa e, Same as 7.. Phenyl Phosphinlc 24, Same as 7 acid, 3 parts. Methylmethacrylate, 100 partsn-gggl sulfite, 3 l8. Styrene, 33.4 pairts;tdsjiethylene 96. 5521 3; gi 6 '6 pm I do Same as 9 1g, Vinyl acetate100 par do 1 Greater than 330 hour Same as 12. bflme as 8 Greateqthtnr330 hr. However, the viscosity was about times that of sample 12 after330 hours.

Prepared by cfiecting reaction 2 Prepared by eficcting reactionv between33 mols propylene glycol, 1 incl tumaric acid, and 2 mols carbicanhydride. (with heat) between 81 parts castor 011 and 17.2 parts maleicanhydride. After cooking to an acid value of about 100-111;decarboxylation is effected by the addition of 1.8 parts pyridine andfurther heating. (See Agens patent 3 The gelling times in these twocases were determined at 132.2 C.

It will be understood by those skilled in the art that the invention isnot intended to be limited to include the specific polymerizablematerials, or organic peroxide catalysts, or accelerators, i. e.,reducing agents, employed in the foregoing examples. Other polymerizablematerials, organic peroxide catalysts, and accelerators as mentionedpreviously (supra) may also be employed in place of the ones used in theforegoing examples. It will be apparent, also, that the benefits derivedat the temperatures employed in the foregoing examples are obtainable,though more pronounced, at higher temperatures, e. g., at 80to 150 C.

By means of my invention, it is possible to polymerize theaforementioned polymerizable materials in situ in shorter periods oftime than has heretofor been possible, while at the same time thepossibility of the development of voids, cracks, etc., in thepolymerized piece is minimized. This is especially useful in the case ofcastings and moldings of such materials which are used, c. g., asdielectrics for capacitors, as bushings, in potting and sealingapplications, or for other electrical insulation purposes.

Advantage may also be taken of the accelerpolymerizable compositions soreadily by means of my claimed invention, it is now economically thepolymerizable mass in suitable solvents may also be effected to yieldmixtures having decreased viscosities suitable, e. g., for deposition onobjects in thin films. Such solutions may be used for wire coatings andother types of insulation including heat and electrical insulation, asacid and alkali-resistant impregnants, etc.

It will, of course, be understood that the polymerizable compositionsdisclosed and claimed in this invention'may be modified furtherby'ineluding fillers opacifiers, pigments, etc.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. The method of polymerizing a non-aqueous polymerizable system free ofunsaturated drying oils and drying oil acids and containing anunsaturated alkyd resin and a terminally unsaturated polymerizableorganic composition in which the terminal unsaturation comprises aterminal ethylenic double bond, which method comprises carrying out thepolymerization in the presence of (a) a vinyl polymerization catalystwhich gives up an atom of oxygen in the presence of phenyl phosphinicacid and is selected from the class consisting of dialkyl peroxides,alkyl hydroperoxides, alkyl esters of peracids, and mixed aliphatic andaromatic peroxides, and (b) from 0.01 to 5 per cent, by weight, based onthe weight of the polymerizable composition of phenyl phosphinic acid,the rate of polymerization being substantially greater than the rate ofpolymerization where the phenyl phosphinic acid is absent.

2. The method of polymerizing a non-aqueous polymerizable system free ofunsaturated drying oils and drying oil acids and comprisingan allylester of a polycarboxylic acid and an unsaturated alkyd resin, whichmethod comprises carrying out the polymerization in the presence of (a)where R is a monovalent hydrocarbon radical selected from the classconsisting of alkyl, aryl, alkaryl, and aralkyl radicals and R is amember selected from the class consisting of hydrogen and alkyl, aryl,alkaryl, and aralkyl radicals, the

- rate of polymerization being substantially greater than the rate ofpolymerization where the organophosphorus compound is absent.

3. The method of polymerizing a non-aqueous polymerizable system free ofunsaturated drying oils and drying oil acids and comprising diallylphthalate and diethylene glycol maleate,

in which the terminal unsaturation comprises a.v

terminal ethylenic double bond and an unsaturated alkyd resin, (2) avinyl polymerization catalyst which gives up an atom of oxygen in thepresence of an organic reducing agent of the class described below in(3) and is selected from the class consisting of dialkyl peroxides,alkyl hydroperoxides, alkyl esters of peracids, and mixed aliphatic andaromatic peroxides, and (3) from 0.01 to 5 per cent, by weight, based onthe weight of the polymerizable composition of an organophosphoruscompound corresponding to the general formula where R'is a monovalenthydrocarbon radical selected from the class consisting of alkyl, aryl,alkaryl, and aralkyl radicals and R is a member selected from the classconsisting of hydrogen and alkyl, aryl, alkaryl, and aralkyl radicals.

5. A composition free of water and free of unsaturated drying oils anddrying oil acids, said composition comprising the product of reaction ofa mixture of ingredients comprising (1) an allyl ester of apolycarboxylic acid'and an unsaturated alkyd resin, (2) a vinylpolymerization catalyst which gives up an atom of oxygen in the presenceof phenyl phosphinic acid selected from the class consisting of dialkylperoxides, alkyl hydroperoxides, alkyl esters of peracids, and mixedaliphatic and aromatic peroxides, and (3) from 0.01 to 5 per cent, byweight, based on the weight of (1), of phenyl phosphinic acid.

6-. A composition free of water and unsaturated drying oils and dryingoil acids, which composition comprises the product of reaction of amixture of ingredients comprising (1) diallyl phthalate diethyleneglycol maleate, (2) tertiary butyl perbenzoate, and (3) from 0.01 to 5per cent, by

weight, based on the weight of (1), of phenyl phosphinic acid.

7. A composition free of water and unsaturated drying oils and dryingoil acids, which composition comprises the product of reaction of amixture of ingredients comprising (1) diallyl phthalate and diethyleneglycol maleate, (2) tertiary butyl hydroperoxide, and (3) from 0.01 to 5per cent, by weight, based on the weight of (1), of phenyl phosphinicacid.

8. The method of polymerizing a non-aqueous polymerizable system free ofunsaturated drying oils and drying oil acids and comprising anunsaturated alkyd resin and a terminally unsaturated polymerizableorganic composition in which the terminal unsaturation comprises aterminal ethylenic double bond, which method comprises carrying out thepolymerization in the presence of (a) a vinyl polymerization catalystwhich gives up an atom of oxygen in the presence of an organic reducingagent of the class described below in (b) and is selected from the classconsisting of dialkyl peroxides, alkyl hydroperoxides, alkyl esters ofperacids, and mixed aliphatic and aromatic peroxides, and (b) from- 0.01to 5 per cent, by weight, based on the total weight of the polymerizableingredients, of an organophosphorus compound corresponding to'thegeneral formula REFERENCES crrEn The following references are of recordin the file of this patent:

UNITED STATES PATENTS Number Name Date 2,356,925 Fryling Aug. 29, 19442,380,473 Stewart July '31, 1945 2,380,475 Stewart July 31, 19452,382,812 Parker Aug. 14, 1945 2,409,633 Kropa Oct. 22, 1946 2,439,214Lindsey Apr. 6, 1948 Brubaker et a1. Feb. 22, OTHER REFERENCES Bacon:Trans. Faraday Soc., Mar.-Apr. 1946, pp. -155.

1. THE METHOD OF POLYMERIZING A NON-AQUEOUS POLYMERIZABLE SYSTEM FREE OFUNSATURATED DRYING OILS AND DRYING OIL ACIDS AND CONTAINING ANUNSATURATED ALKYD RESIN AND A TERMINALLY UNSATURATED POLYMERIZABLEORGANIC COMPOSITION IN WHICH THE TERMINAL UNSATURATION COMPRISES ATERMINAL ETHYLENIC DOUBLE BOND, WHICH METHOD COMPRISES CARRYING OUT THEPOLYMERIZATION IN THE PRESENCE OF (A) A VINYL POLYMERIZATION CATALYSTWHICH GIVES UP AN ATOM OF OXYGEN IN THE PRESENCE OF PHENYL PHOSPHINICACID AND IS SELECTED FROM THE CLASS CONSISTING OF DIALKYL PEROXIDES,ALKYL HYDROPEROXIDES, ALKYL ESTERS OF PERACIDS, AND MIXED ALIPHATIC ANDAROMATIC PEROXIDES, AND (B) FROM 0.01 TO 5 PER CENT, BY WEIGHT, BASED ONTHE WEIGHT OF THE POLYMERIZABLE COMPOSITION OF PHENYL PHOSPHINIC ACID,THE RATE OF POLYMERIZATION BEING SUBSTANTIALLY GREATER THAN THE RATE OFPOLYMERIZATION WHERE THE PHENYL PHOSPHINIC ACID IS ABSENT.